Device for assisting navigation



sept. 15,1925. 1,553,771

w. `HAM-INEMANN DEVICE FQR ASSIS'I'ING NAVIGATION Fll F55. 4, 1921 manen.' 9719;."

For/11709 cfm/16E avE/2 JW/ TCH yPatented Sept. l5, 1925. I

'UNITED ASTATES PATENr'ol-#Flcag WALTER HAHNELIANN, F XITZEBERG, NEAR KIEL, GEEMANY, ASSIGNOR T0 THE FIRE SIGNAL GESELLSCHAFT MI. B. H., 0F KIEL, GERMANY.

DEVICE FOR ASSISTING- NAVIGATION.

Application led Tebruary 4, 1921. Serial No. 442,579.

To all lwhom 'it may concern:

Be it known that I, .WALTEni-HAHNEMANN, Y

citizen ofthe German Republic,and residing' at Kitzeberg, near Kiel, county of Schleswig-Holstein, State of Prussia, Germany, have invented certain new and vuseful Improvements in and Relating to Dev vices for Assisting Naviga-tion, of which the following ils a specification.

The invention is concernedlwith a method of cable signalling in which alternating 'currents liow in one or more cables located 4on the bottom of -the channel to be navigated, which currents operate by induction an indicating apparatus carried on the ship. One diiiculty in these -methods consists in finding the beginning point of the cable upon the approach of the vessel. t

For this purpose auxiliary devices are provided by this invention. It consists in `placing a sound transmitter in the water at the end of the cable.

The transmitter is preferably in the form of an electrically driven transmitter-andl its current supply can be maintained through' the cable itself.V

The considerably greater range of the sound signals of a powerful sound transmitter ta,- cilitates the finding of the ends of the cable and enables the vessel to be navigated to the beginning of the'channel indicated by the cable.

In the simplest form of my invention vthe same current `which flows in the cable isy employed for operating the sound transmitter. These currents are alternating currents and generally of a frequency which is capable of producing a suitable Warning tone. intermittently switched in and out by means of an interrupter or key situated onland or are switched from one cable to another cable. AIf the sound transmitter is connected by means of a. change-over switch alternate-v 1 .to a number of cables in rotating sequence, le wave impulses which ow consecutively through the several cables to the transmitter may produce continuous tones therein which may be unsuitable ihr reception. on

account of their similarity lto extraneous noises arising from the water. Therefor,

preferably an interrupter is suitably connected 4to the `conductor which connects the generator with the cable. Such interrupter chops up the continuous impulses and proi duces in the transmitter a predeternned They are ordinarily` sound signal,forfexamp1e consisting of a .series of dashes. The interrupterl can be inserted between the machine and the cable as well as between the cable and transmitter.'

In the first case there is the adv tage that the interrupter can be installedon the land,

aov

but the ydisadvantage-that the alternating currents in the cable likewise give the same ondI case the diiiculty must be taken into consideration which arises from placingI the interrupter under water.

In the accompanying drawing some examples of carrying out the invention are il-v lustrated.

' signal as the sound transmitter; in the sec- 'zov Fig. 1 shows an arrangement with a cable Inall the figures 1 indicates an alternating current machine,A which supplies the conductor consisting of the cable 2 or of a plurallty of cables 2 and 3.

7 is inserted in the ca le 2 between the In thefexample of Fi 1 an interrupter l machine 1 and a sound transmitter consisting'of a diaphragm 5 and a magnet system 6.

According to Fig." 2a rotating changeover-switch 4, driven by a motor not shown in the drawin s, alternately connects at regular interva s successivel one or the other of the two cables 2` an chine 1. One end of the magnet winding of the sound transmitter 5, 6 (consisting` of a diaphragm 5 anda magnet system 6) is connected to the ends of the cables which arel joined together. The other end `of the magnet system is earthed as is also the secon alternating current. ma-

pole of the chinel. Y .l In the example shown in Fig. 3 a motor driven interrupter 7,L is inserted between the machine 1 and the switch 4 which inter-l rupts the continued( alternatingcurrent from the 'machine "'rlodically. The interruption is preferab y timed soy that a num-` 3- to the ma- A sub-divided into dashes and spaces.

ber of alternate connections take place at 4 in each period.

The insertion of the interrupter between .the outer ends of the cables and the transmitter is more preferable for giving signals even if it is more diflicult technically since then the signals remain unaltered in the cables while the tone of the transmitter i s Such an arrangement is shown in Fig. 4. The cable current is alternately conducted, by means of an interrupter 7 driven by an alternating current motor 8, to earth through the transmitter 5 or through a 4substitute aggregateA consisting of a resistance 9 and inductance coil 10. For driving the mot-or 8 a conductor can be branched from the cable leading to the interrupter,

The different connections'posslble for the sound transmitter and the possible kinds of lsignalling which can be employed with an arrangement constructed in accordance with the-invention are not intended to be limited to the actual forms shown. For instance the constructive form ofthe sound transmitter is. without im ortance sov far as the essential features o the present invention are concerned.

I claim:

1. In combination with a pilot conductor disposed under water on a predetermined line and carrying alternating currents suplied to it at one end for the purpose of mdicating the said line, an electric submarine sound transmitter submerged at and connected to the outer end of the conductor and adapted to be operated by alternating current.

2, In combination Iwith a pilot conductor disposed under Water on a predetermined line and carrying alternating currents suplied to it at one end for the purpose of indicating the said line, an electric sound transmitter submerged immediately adjacent to the outer end ofv the'conductor and Operatedby alternating current, and an interrupter adapted to cause the transmitter to emit predetermined sifrnals.

3. In combination with a pilot conductor disposed under water on a predetermined line and carrying alternating 'currents supplied to it at one end for the purpose of indicating the said line, an electric sound transmitter submerged at and ,connected to 'the outer end of the conductor and adapted to be operated by alternating current, an interrupter for interrupting the alternating currents' at certain intervals so as to cause the said transmitter to emit predetermined signals, an electric motor also operated by the said current for driving-the said interrupter, both the motor and the interrupter being located at the outer end of said 'conductor.

In testimony whereof I alix my signature.

WALTER HAHNEMANN. 

